Various plastics, e.g., polyethylene terephthalate, have been conventionally used as materials for bottles of juices, natural water, tea and other drinks. The plastic bottles are usually disposable, but they have been recently required to be recovered and recycled after use from the viewpoints of saving energy and saving natural resources.
For recycling the plastic bottles, the bottles are washed and sterilized to remove organic or inorganic substances attached thereto and adsorbates such as substances having a taste or a scent adsorbed thereon, and then filled with contents. Even if the attached substances are completely removed by the washing, however, it is difficult to completely remove the adsorbates from the bottles. Therefore, after filling of the contents, the adsorbates are transferred to the contents thereby, to cause deterioration of the taste or the scent of the contents.
In order to recycle the bottles, accordingly, it is necessary that the bottles have small adsorption of the substances having a taste or a scent, i.e, excellent non-adsorptivity, and have high heat resistance capable of withstanding filling of high-temperature liquids which have been subjected to heat sterilization after washing. Further, also necessary is that the attached substances or the adsorbates are completely removed from the bottles.
The present inventors have earnestly studied to solve such problems associated with the prior art technique as mentioned above, and as a result, they have found that a bottle made of a specific polyester and having a high mean crystallinity at the bottle body is excellent in non-adsorptivity and heat resistance. They have also found that if the bottle having a high mean crystallinity at the bottle body is held in air or brought into contact with water or water vapor of a specific temperature, the adsorbates on the bottle can be rapidly desorbed. Based on these findings, the present invention has been accomplished.